Although the goal of developing school students’ understanding of nature of science (NOS) has long been advocated, little is known about how science teachers, a kind of major stakeholder in NOS instruction, perceive the values of teaching NOS. Through semi-structured interviews, this study investigated the views of 15 Hong Kong in-service teachers toward the values of teaching NOS. The values of teaching NOS as perceived by the teachers fall into two types. The first type is related to students’ learning of science in the classroom and involves (i) facilitating the study of subject knowledge, (ii) increasing the interest in learning science, (iii) aiding the conduct of scientific inquiry, (iv)meeting the needs of public examination, and (v) fulfilling the inherent requirement of scientific learning. The second type goes beyond learning science and includes (i) developing thinking abilities, (ii) cultivating scientific ethos, and (iii) supporting the participation in public decisions on socioscientific issues. Although rich relationships were perceived by these teachers between NOS instruction and students’ learning of science, few values were stated from broad social and cultural perspectives. Suggestions are made on designing programs to prepare teachers for teaching NOS.